The researchers highlighted the serious risks of climate change destabilising Earth’s tipping features, such as ice sheets and ocean currents, and stressed that the 1.5°C limit set by the Paris Agreement must be maintained to avoid dire consequences in the future. Failure to meet these limits increases the likelihood of tipping events, significant changes that could affect global climate stability for centuries.
Anthropogenic climate change can destabilize large-scale components of the Earth system, called overturning elements, such as ice sheets or ocean circulation patterns. While these components may not change immediately, fundamental processes are set in motion over tens, hundreds, or thousands of years. The researchers say these changes are so severe that they should be avoided at all costs.
In a new study published today (August 1) Nature CommunicationThey estimated the risk of at least one tipping element becoming unstable as a result of a temperature increase of 1.5°C. Their analysis shows how important it is for the state of the planet to meet the climate goals of the Paris Agreement. This further highlights the legacy of today’s climate inaction across centuries and millennia.
Assessing spillover risks under current climate policy
“Although the timeframe to 2300 or beyond seems very difficult, it is important to identify the risks of tipping as much as possible. Our results show how vital it is to reach and maintain net zero greenhouse gas emissions to limit these risks for the next hundreds of years and beyond,” explains lead author Tessa Möller, a scientist at IIASA and PIK. “Our calculations show that following current policies until the end of this century would lead to a 45 percent increased risk of exposure to at least one of the four elements by 2300.”
Increasing risks with rising global temperatures
“We see that the risk of overturning increases with every ten-degree increase above 1.5°C. But if we exceed 2°C of global warming, the risk of overturning will increase even faster. This is very worrying because scenarios consistent with current climate policy are projected to lead to global warming of around 2.6°C by the end of this century,” says Annika Ernst Hegner of PIK, who led the study.
The urgency of reaching zero emissions
“Our study confirms that the risk of tipping over in response to extremes can be minimized if warming is rapidly reversed. Such reversal of global warming is only possible if greenhouse gas emissions reach at least net zero by 2100. The results underline the importance of the Paris Agreement’s climate targets to limit warming to well below 2°C, even in the event of temporary extremes above 1.5°C,” says study author Nico Wunderling from PIK.
The importance of limiting global warming to 1.5°C
The four overturning elements analyzed in the study play a key role in regulating the stability of the Earth’s climate system. So far, complex models of the Earth system have not yet been able to comprehensively model its nonlinear behavior, feedbacks, and interactions among some overturning elements. Therefore, the researchers used a stylized model of the Earth system to represent the key properties and behaviors, thus systematically incorporating relevant uncertainties into the overturning elements and their interactions.
“This landmark risk analysis further supports the conclusion that we have underestimated the risks, and it is now necessary to recognise that the Paris Agreement’s legally binding target of keeping global warming ‘well below 2°C’ actually means limiting global warming to 1°C. 0.5°C. Due to insufficient emissions reductions, the risk of us exceeding this temperature limit over a period of time is increasing, and we must minimise this at all costs to reduce the dire impact on people worldwide,” concludes the study by PIK director and author Johan . Rockstrom
Source: Port Altele
